I only know of renraku waza being used in Judo. Isn't the idea of renraku to apply a technique that you know your attacker will counter a certain way, so it sets up your next technique?
These things all sound close, and of corse you can use words to describe what ever you want (as long as others get your meaning). But it seems all of these have a slightly different meaning.
I learned henka waza to mean subtle variations in the same technique. Like Saito's different morote dori entries.
However the Aikiwiki definition of henka to me sounds like it means a technical flow from one failed technique to the next. Example:
I applied ikkyo, uke locked his arm straight, so I applied rokyo to his straight arm.
Then you've got renzoku waza, which I understand to be continuous technique. Not necessarily based on uke's response, but just as a part of what happens. Example:
I applied ikkyo, uke locked his arm straight, so I kicked him in the ribs.
Then you have renraku waza, which as I understand it is used like this. Example: I applied ikkyo, because I knew he would straighten his arm, that gave me the head start to apply a perfect rokyo.
Then one that has not yet mentioned is: Kaeshi waza. Example: I tried to apply ikkyo, uke locked his arm straight and threw me with kokyu nage.
As a general rule I use the word Kaeshi anytime uke is changing so nage has to adjust, but I'm starting to think there is a good reason for further clarification of terms...
I understood henka wasa to cover any change in the technique.
You change due to tactical consideration.
Ie you started ikkio, someone was coming so you straighten his arm and rokkyo him.
You change du to uke resistance
He straighten his arm to resist ikkio, hence rokkyo.
I think in includes the case where I expected the arm straitening or because I have awase and I felt the defence and adapted to it.
I have the same understanding of keishi wasa as Chris